I've tried to integrate the video.js plugin for Redactor. It allows me to insert a YouTube embed (as expected) but the iframe code is stripped out on save. Using the latest Craft 2.5 build. Anyone experienced the same? Solutions?
You've probably got "Purify HTML" checked under your Rich Text field's settings and that's stripping iframe code.
You should really only have that checked if you're accepting input from untrusted sources using the Rich Text field on the front-end of your site. Presumably all users using the control panel are trusted enough not to input malicious code into the site.